An Improved DC-Link Voltage Control Strategy for Grid Connected Converters

Abstract

This paper presents a robust control strategy to improve dc-link voltage control performances for grid-connected converters (GcCs). The proposed control strategy is based on an adaptive proportional integral (PI) controller and is aimed to ensure fast transient response, low dc-link voltage fluctuations, low grid current total harmonic distortion, and good disturbance rejection after sudden changes of the active power drawn by the GcC. The proportional and integral gains of the considered adaptive PI controller are self-tuned so that they are well suited with regard to the operating point of the controlled system and/or its state. Several simulation and experimental results are presented to confirm and validate the effectiveness and feasibility of the proposed dc-link voltage control strategy.